Now hailed by many as one of the great street photographers of the 20th century, Maier made her living as a nanny. While combing the streets of Chicago, New York, and other cities with her young charges in tow, she made more than 100,000 images, often stashing away the undeveloped film and negatives in suitcases. After her death in 2009, John Maloof unwittingly acquired a trove of Maier’s negatives at auction. Overwhelmed by what he found, he has subsequently set out to uncover Maier’s story and publicize her work; this brilliantly told chronicle is part of that process. Maloof narrates and codirects (along with Charlie Siskel) the doc—which is by turns poignant, humorous, and a bit disturbing as acquaintances recall Maier’s odd life and experts evaluate her skills. The film explores both sides of the debate over whether Maier meant for her work to remain unseen.